While many Neolithic cultures continued to use stone tools, they also developed copper and ultimately bronze metallurgy, leading early scholars to coin the term “Chalcolithic” (copper-stone) to distinguish them from earlier Neolithic and Paleolithic cultures.
The earliest manufactured alloy, bronze is made with copper and tin ores (and consequently required trade with remote ore-producing regions). Gold and copper had formerly been smelted, mainly for decorative purposes, but bronze tools and weapons outlived and outperformed stone. From circa 3500 CE, their use spread from Mesopotamia, with separate cultures amending recipes and techniques. The later discovery of similar techniques in the Americas seems unconnected.
Bronze age is the epoch between the human cultural development between the Neolithic period and the discovery of iron-working techniques (the Iron Age). In Mesopotamia, bronze tools were used from c.3200 BCE and the Bronze Age lasted until c.1100 BCE. In Britain, bronze was used after 2000 BCE and iron technology did not become prevalent until c.500 BCE.
Ireland had rich sources of copper ores, specifically in the southwest, which were recognizable by these early prospectors, and which resulted in the development of a significant copper- and later, bronze-working industry. In Britain and Ireland the beginning of the Bronze Age is marked by the appearance of metalworking, new burial practices, and an growth in trade and exchange.
Tools and swords that outlived their owners made inheritance and theft possible, and as cities developed, so did professional armies. Fields could be ploughed and harrowed, and older clay and wax technologies were put to use in metal casting. Early experiments with iron ore produced a brittle, corroding metal, but around 610 BCE, climate changes triggered mass migrations that made local iron ore mining in Europe easier than importing tin. Elsewhere, notably in Japan and southern Africa, bronze and iron arrived more or less concurrently.
From about 700 BCE a steady change from a mainly bronze-working economy to one based on the use of iron as the preferred metal took place. These changes were intense and irreversible, affecting all aspects of society. Ultimately, iron replaced bronze as the preferred metal for the production of tools and weapons, and bronze was restricted mostly to objects of a more decorative nature.
The working of iron was introduced, probably from Asia Minor (modern day Turkey,) into southeastern Europe around 1000 BCE, and into central Europe by the 8th—7th centuries BCE. The European Iron Age has conventionally been divided into two phases, named after type-sites at Hallstatt in Austria and La Tene in Switzerland. In areas conquered by the Romans the ‘Iron Age’ is succeeded by the ‘Roman’ period. Contemporary cultures outside the empire are designated as being of the ‘Roman Iron Age’. From about 400 CE these periods are succeeded by the migration period.